Nathaniel w



(No Model.) N. W. PRATTKE G. E. PALMER.

1 FURNACE FOR THE COMBUSTION 0P BITUMINOUS GOAL.

No. 312,655. Patented Feb. 24, 1885.

W NESSES: INVENTORS W W 2 r I BY "WWW W W ATTORNEY Nrrn STATES. PATENTNATHANIEL W. PRATT, OF BROOKLYN, NEWV YORK, AND GEORGE E. PAL- MER, OFCHICAGO, ILLINOIS, ASSIGNORS TO THE BABGOOK & \VILOOX COMPANY, OF NEWJERSEY.

FURNACE FOR THE COMBUSTION OF BlTUMlNOUS COAL.

SPECIFICATION forming part of Letters Patent No. 312,655, dated February24, 1885.

(No model.)

To aZZ whom it may; concern:

Be it known that we, NATHANIEL W. PRATT, of Brooklyn, in the county ofKings and State of New York, and GEORGE E. PALMER, of Ohicago, in thecounty of Cook and State of Illinois, have made a joint invention ofcertain new and useful improvements in furnaces for the combustion ofbituminous coal or fuel having similar characteristics; and we do hereby1Q declare that the following is a full, clear, and

exact description and specification of the same.

Our invention is especially applicable to furnaces where such fuel isused for the generation of steam; and its object is to secure as much aspossible of the heating value of the fuel by retarding the escape of thehot products of combustion, and securing their proper application to thesurfaces tobe heated, and their even distribution over such surfaces. Inorder to fully and clearly illustrate our plan of construction, and asour invention includes also an advantageous method of applying it towater-tube boilers, we have shown it in the accompanying drawings, andwill pro- 2 5 ceed to describe it in connection with so much of such aboiler as is necessary to illustrate the manner of so applying anddistributing th heat.

In said drawings, Figurel showsa sectional side elevation of saidfurnace, and Fig. 2 a front sectional elevation, showing a single anddouble furnace.

Ais the combustionchamber,into which the fuel is fed in the usualmanner, and is formed 3 5 by the grate G and the side walls supportingan arch, J. This grate G is preferably dropped at the rear end for thepurposes of facilitating combustion and also obtaining an enlargedfurnace-area without increasing the grate-surface. 0 From thiscombustion-chamber A a contracted opening, H, leads into theretarding-chamber B, the rear wall, L, of which forms the base of abridgewall, (separating the water-tubes,) and the crown D,which is inthis case formed 5 of brick, as shown at N, surrounding and supported bythe. water tubes. From the retarding chamber a contracted opening, I,smaller than the opening H, leads between the arch J and the crown Dinto the distributingchamber 0, where the furnace products, after havingample time for combustion and combination, and having therefore passedonly over fire-brick surfaces, are finally distributed over the surfacesupon which they are to act.

It is very desirable in the case of furnaces of great Width,frequentlyused for boilers of large capacity, to avoid cooling of the whole of thefurnace at once by opening a firedoor, and it is alsodesirable to gainstrength and durability by making the arches J J as narrow as pos- 6osible. WVe accomplish both these results by the means of double furnace,(shown in Fig. 2,) where M is a mid-- wall running parallel with thegrates, and dividing the furnace into two portions covered by two archesabutting against said mid-wall. Both divisions connect with a commonretarding-chamber constructed as already described, the saidretardingchamber opening into the distributing-chamber.

By arranging the combustion and distributing chambers separatedby asolid or imperforate arch or arches in the same vertical plane, and byplacing the retarding-chamber at the rear of the combustion anddistributing cham- 7 5 bers, partly above the one and partly below theother, so as to communicate with both,we secure compactness withexcellent results, the opening from the retarding-chamber into thedistributing-chamber being preferably smaller than the opening from thecombustion-chamber into the retarding-chamber to impede the passage ofthe gases somewhat, and thus insure more perfect combustion.

\Ve claim as our invention 1. In a boiler-furnace, the combination ofcombustion and distributing chambers, both arranged in the same verticalplane, an arch separating said chambers, a retarding-chamber arrangedentirely rearwardly of the said-con1- o bnstion and distributingchambers, and having at its top a fire-brick crown sustained by thelower heating-surfaces of the boilers, the passage-way between thedistributing-chamber and the retarding-chamber being smaller than thepassage-way between the latter chamher and the combustion chamber,substantially as set forth.

ber, and a distributing chamber arranged above the saidcombustion-chamber, said re tarding and distributing chambers being both15 common to the several compartments of the combustion chamber,substantially as set forth.

NAT. WV. PRATT. GEORGE E. PALMER.

Witnesses:

J OHN E. EUsTIs, Gno. A. HOWELL, JOHN W. PAGE, MILTON THOMAS.

